It is known to provide sampling and/or measuring apparatus for immersion in molten metal. The apparatus typically includes a lance on which it is removably mounted a disposable probe. A lance is typically made of metal whereas the disposable probe includes a tube of paperboard which is telescoped over an immersion end portion of the lance with a force fit until the end of the tube engages a shoulder on the lance. The probe at the end thereof remote from said shoulder typically supports a sampling chamber and/or one or more sensing elements.
The sensing elements supported by the disposable probe are electrically coupled to a connector on the tube. The connector on the tube is coupled to contacts on the lance. The contacts are coupled to recording instruments by way of wires which extend through the hollow lance. When the apparatus is used in connection with a converter, the probe is vertically immersed into the converter adjacent to the oxygen supply lance.
Apparatus in accordance with the present invention has considerable length and can be as long as 20 meters. It is necessary to take samples and/or measurements when the bath is under relatively calm circumstances as well as when the bath is turbulent such as during the oxygen blow. As a result of the length of the lance, and under turbulent circumstances, the lance vibrates. When the lance is immersed into the molten bath, liquid metal and slag will splash upwardly. It is possible for such splash to solidify and result in a deposit of frozen metal on the joint between the shoulder of the lance and the upper end of the probe tube. When a new probe is telescoped onto the lance, the frozen metal interferes with proper mating of the connector and contacts and also interferes with a good mechanical connection between the probe and the lance. As a result thereof, an improper reading may be obtained.
The present invention is directed to the solution of the problem of how to prevent the deposit of frozen metal at the joint between the probe and the lance.